The objectives of the Registry of Experimental Cancers are the storage and retrieval of pathologic material and data on cancers and other lesions of laboratory animals (primarily rodents) and the use of such information for research and educational purposes. The Registry has acquired a total of 2,219 (90 since the 1982 report) single or group accessions from investigators outside the NCI. Approximately 56,285 records have been prepared for coding and coded. Thirty-nine investigators have come to the Registry for study and consultation on single or multiple vistis. One foreign investigator was a guest at the Registry for one week.